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<?xml-stylesheet type="text/xsl" href="https://communities.bentley.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>Partially Closed Valves in water supply system</title><link>https://communities.bentley.com/products/hydraulics___hydrology/f/haestad-hydraulics-and-hydrology-forum/217898/partially-closed-valves-in-water-supply-system</link><description>Hello, 
 I&amp;#39;m modeling a high pressured water supply system full of partially closed valves (which people use as some kind of &amp;quot;prv&amp;#39;s&amp;quot; to reduce pressure because they don&amp;#39;t have enough money to buy it). The information they gave me is D(mm) of a valve,</description><dc:language>en-US</dc:language><generator>Telligent Community 12</generator><item><title>RE: Partially Closed Valves in water supply system</title><link>https://communities.bentley.com/thread/665554?ContentTypeID=1</link><pubDate>Tue, 10 Aug 2021 12:39:06 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:ab9b0b73-45bb-4ed6-a8ab-d4e8374e6814</guid><dc:creator>levon batoyan</dc:creator><description>&lt;p&gt;Thanks for all of your responses,&lt;span&gt;&lt;br /&gt;&lt;br /&gt;the system is very old with&amp;nbsp;high NRW, we inherit it from the soviet union.&amp;nbsp;Operators&amp;nbsp;are doing this to reduce NRW until directors find the money for prv&amp;#39;s.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span&gt;In this case, it is a globe valve, which is adjusted annually.&lt;/span&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Partially Closed Valves in water supply system</title><link>https://communities.bentley.com/thread/665546?ContentTypeID=1</link><pubDate>Tue, 10 Aug 2021 11:50:34 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:af9d0270-1868-41bb-b8f4-dfa6933f2a5f</guid><dc:creator>Tom Walski</dc:creator><description>&lt;p&gt;To answer this question, I would need to know the type of valves you are using and how they are operated. Are these gate valves, butterfly valves, globe valves,...? Are they&amp;nbsp;adjusted hourly, daily, annually, never?&lt;/p&gt;
&lt;p&gt;The simplest way to model this is to develop a curve of percent open vs. minor loss K and knowing the percent open, you can either use a TCV or simply put a minor loss on the pipe where the valve is located. Knowing the percent open of each valve for 100 valves can be difficult, especially if they are frequently adjusted by a range of human operators who may not communicate the status to the modeler.&lt;/p&gt;
&lt;p&gt;I have a problem understanding why anyone would operate their system like this. Manually throttling a valve to control pressure results in the valve being closed significantly during low flow periods. However,&amp;nbsp; when a high flow is needed, these valves dramatically reduce system capacity. Remember that head loss is a function of flow squared. It&amp;#39;s like paying for a 200 mm pipe but converting it into a 50 mm pipe.&lt;/p&gt;
&lt;p&gt;In general, this is not a good way to operate a system. It is better to define pressure zones and feed them through PRVs. A PRV can maintain a good pressure during low demand times but when demand increases, can open wider to enable a large flow to pass. There is no need to put an FCV in series with a PRV unless you are actually installing such a configuration.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Partially Closed Valves in water supply system</title><link>https://communities.bentley.com/thread/665538?ContentTypeID=1</link><pubDate>Tue, 10 Aug 2021 11:08:08 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4f3c876d-628c-4170-803a-931d3b16a027</guid><dc:creator>levon batoyan</dc:creator><description>&lt;p&gt;Hi Sushma,&lt;/p&gt;
&lt;p&gt;I&amp;#39;m using TCV, steady-state condition.&lt;br /&gt;&lt;br /&gt;I don&amp;#39;t know how to represent a valve that is partially closed.&lt;br /&gt;&lt;br /&gt;(&lt;span&gt;for instance, in real life pressure before and after the valve is 75m, valve D=150mm.&amp;nbsp;After partially closing&amp;nbsp;TCV pressure becomes after the valve 20m and 5 l/s flow goes through it.)&lt;/span&gt;. how to simulate this?&lt;/p&gt;
&lt;p&gt;&lt;br /&gt; What would you do?&lt;br /&gt;&lt;br /&gt; Would it be&amp;nbsp;&lt;span&gt;precise to put PRV+FCV&amp;nbsp;to simulate partially closed TCV? or there are other options?&lt;br /&gt;&lt;br /&gt;&lt;/span&gt;in my city model, I have more than 100 such kinds of situations.&amp;nbsp;&lt;br /&gt;&lt;br /&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Partially Closed Valves in water supply system</title><link>https://communities.bentley.com/thread/665471?ContentTypeID=1</link><pubDate>Tue, 10 Aug 2021 07:57:21 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:bcbb8715-9f63-4b01-acff-77ea7b988f47</guid><dc:creator>Sushma Choure</dc:creator><description>&lt;p&gt;Hello Levon,&amp;nbsp;&lt;/p&gt;
&lt;p&gt;Which valve element you are using to model partially closed valves? Is it TCV?&amp;nbsp;&lt;/p&gt;
&lt;p&gt;Are you changing the closure % of valve time to time during EPS or is it constant?&amp;nbsp;&lt;/p&gt;
&lt;p&gt;Please read more about calculating headloss coefficient and modeling valve closure using link below.&amp;nbsp;&lt;/p&gt;
&lt;p&gt;&lt;a href="/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/10424/configuring-tcv-relative-closure-patterns-for-eps" rel="noopener noreferrer" target="_blank"&gt;Configuring TCV relative closure patterns for EPS&lt;/a&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;&lt;a href="/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/26424/how-are-headlosses-determined-for-tcv-s-with-the-different-initial-status-settings" rel="noopener noreferrer" target="_blank"&gt;How are headlosses determined for TCV&amp;#39;s with the different initial status settings?&lt;/a&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;If this is not what you are looking for then please elaborate your query.&amp;nbsp;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>